The statements in this section merely provide background information related to the present disclosure. Accordingly, such statements are not intended to constitute an admission of prior art.
Hybrid powertrain architectures can include multiple torque-generative devices, including internal combustion engines and non-combustion torque machines, e.g., electric machines, which transmit torque through a transmission device to an output member. Known hybrid powertrain systems may be configured to operate in continuously variable states and fixed-gear states, one embodiment of which includes a two-mode, compound-split, electro-mechanical hybrid transmission. In one embodiment, such a hybrid transmission includes an input member for receiving tractive torque from a prime mover power source, preferably an internal combustion engine, and an output member. The output member can be operatively connected to a driveline for a motor vehicle for transmitting tractive torque thereto. Torque machines, operative as motors or generators, can generate torque inputs to the hybrid transmission independently of a torque input from the internal combustion engine. The torque machines may transform vehicle kinetic energy transmitted through the vehicle driveline to energy that is storable in an energy storage device. A control system monitors various inputs from the vehicle and the operator and provides operational control of the hybrid powertrain, including controlling transmission operating state and gear shifting, controlling the torque-generative devices, and regulating the power interchange among the energy storage device and the machines to manage outputs of the transmission, including torque and rotational speed.
Hybrid transmissions configured to operate in multiple continuously variable states execute shifts therebetween. Shifts between continuously variable modes may be commanded and executed independently of changes in operator torque demands. A shift between continuously variable states may be executed using an intermediate operation in neutral, referred to as a shift-through-neutral event.